1. Field of the Invention
This invention relates generally to apparatus and methods for engaging and holding tissue, and more specifically to such apparatus and methods involving use of a suture.
2. Discussion of the Prior Art
When a wound is created in body tissue, either intentionally in the case of an incision, or unintentionally in case of an accident, it is desirable to close the site by engaging tissue portions on either side of the separation and drawing those portions into close proximity. Over time, tissues in close proximity will form a scar closing the wound.
Wound-closure systems of the past have included adhesives and clamps. However, the most common closure devices typically involve sutures which can be threaded through the opposing tissue portions and pulled tight to close the wound. In order to hold the suture taught over an extended period of time, a knot is commonly formed in the suture ends. Most surgeons would agree that suturing is an art form learned over an extended period of time. There are many types of sutures and knots, each providing certain advantages in a particular operative setting. At least as complicated as the suturing itself is the knot-tying which must occur to secure each of the sutures. Where individual sutures are placed to close a long wound, an individual knot must be tied in each place.
Knots differ considerably in their configuration, function, complexity, and characteristics. By way of example, it will be noted that knots typically involve several throws of the suture ends relative to each other. In one common knot, three half-hitches are used with the first half-hitch having four throws and each subsequent half-hitch having three throws. In this case, the tying of a single knot to close a single suture involves ten throws. The simpler knots may be easier to tie, but in distant locations even the simple knots can be complicated where it is difficult to achieve proximity to the suture site. In these locations, more complicated slip knots have been used. These knots can be tied at a remote location and then slipped down to the surgical site. Except for a few extremely complex knots, such as the Tayside knot or Roeder, slip knots have the undesirable tendency to slip in both directions. As a result, their ease of tying and movement to the surgical site is offset by their tendency to lose their grip at the suture site.
From these few examples it can be appreciated that knots, as a suture-closing system, are time-consuming, difficult to tie, hard to place, often unreliable as a holding system, difficult to adjust and impossible to relocate. Especially in the context of a laparoscopic procedure, it is noteworthy that the surgeon may lose the tactile feedback associated with tension on the suture as the knot is being tied due to the remote nature of the laparoscopic modality.